i2c: imx: preserve error state in block data length handler

In the Linux kernel, the following vulnerability has been resolved: i2c: imx: preserve error state in block data length handler When a block read returns an invalid length, zero or >I2C_SMBUS_BLOCK_MAX, the length handler sets the state to IMX_I2C_STATE_FAILED. However, i2c_imx_master_isr() unconditionally overwrites this with IMX_I2C_STATE_READ_CONTINUE, causing an endless read loop that overruns buffers and crashes the system. Guard the state transition to preserve error states set by the length handler.